Douglas Elliman broker Oren Alexander in Bal Harbour, Fla., where he’s working on a $25 million mansion.Manny Hernandez

My father is a residential developer, and I started seeing his work at a very young age, checking out incredible construction and architecture while my friends were doing math homework. Real estate became my greatest interest and after graduating from the University of Colorado, I moved to New York to work in the industry.

I always imagined that I would sign with a development firm and receive a typical starting salary and grow in the company. But it was 2008 and Lehman had just collapsed. I was so clueless that when I was introduced to Howard Lorber, the chairman of Douglas Elliman, my first question was what my salary would be. He chuckled and informed me that real estate brokers work on commission. I would be an independent contractor.

The first few months were difficult. I wasn’t licensed yet, the slow winter season started, and I needed to make my rent. But then my first deal happened in March 2009. I sold an $8.175 million penthouse at the Park Imperial. I was only 21. Everything got better from there.

I think you really have to come from a point of desperation to be successful. That sale gave me some credibility. And it helped me realize that I wanted to focus on the market’s upper 5 percent. I’ve sold all over Manhattan. One highlight was a prewar co-op at the Eldorado on Central Park West. Young brokers aren’t known for doing deals like this. I was 23. Now I’m 25.

My team — the Alexander Group — with my brother, Tal, just cracked the trophy market. I sold a house in Miami that my dad built for $47 million over the summer. The price for that house at 3 Indian Creek was a Miami record. I now have a listing in Alpine, NJ, for $49 million.

I do work in New York, Miami, the Hamptons, Aspen and Tel Aviv. My goal is to sell trophy homes worldwide. There are only a few buyers for this type of real estate in the whole world. Knowing them means I can to sell them in New York, Miami, St. Tropez, anywhere.

The average day for me is never the same, but I usually start with yoga or a run, then have breakfast with a client and then meetings and showings all day. Lunches and cocktails turn into dinners, and the real work begins when I go out after. My late hours are my favorite part of the day, when I merge my two passions: meeting people and talking real estate. This is my time to bring in new business. My clients go to those absurdly expensive and elite places that no one can get into; I have my in. While my nights are late, and some may call me a party boy, it’s all about closing deals. And my team never stops working, either.

THE PARTNER: My partner also happens to be my brother, Tal Alexander. He’s 11 months older than me. We joined forces about two years ago. Ever since we teamed up, our business has been taken to the next level. I rely on him for everything. I think the level of trust we have is the key to our success. I know that if he’s working with a client they’ll have as good or better service than they’d have with me.

THE MENTOR: Whenever I’m going after big business or new developments, I go to Howard Lorber, the chairman of Douglas Elliman, first. I speak with him on a weekly basis. He taught me to look at the big picture and not to get caught up on the small things. He’s big on the macro level. My father likes to call him my second father.

THE BUILDER: My father, Shlomi Alexander, built the first trophy house I sold. That’s the $47 million house. He’s built about 12 homes, but this was the first time that we worked together. Now, we have two more projects in the works, both of which are in Miami. When I’m in Miami on a Friday night, we have Shabbat dinners which basically turn into board meetings. I act as the consultant on design and architectural plans and finishes and he’s the developer and the builder.

THE PHOTOGRAPHER: Evan Joseph is the best photographer I’ve ever worked with. He shoots all my high-end property. The first time we worked together was on my Central Park West listing and now he’s doing my $49 million mansion in Alpine. He just has this way of capturing the atmosphere in every room.

THE ARCHITECT: Chad Oppenheim creates environments you can really live in. His work is simultaneously dramatic and comfortable. He’s designing a tropical modern house in Bal Harbour that my father is building. I’m marketing it, of course, but I’m also developing it, putting up my own money. That’s how much I believe in the trophy market.